Sea level settles
After 120 metres of rise the oceans reach roughly their modern level and coastlines stop moving.
- When
- Known to
- ± 300 years
- Era
- Neolithic, Holocene
Meltwater input falls away as the great ice sheets finish disintegrating, and by around 4000 BCE global sea level is within a few metres of present and rising only slowly. Stable coastlines allow deltas to build, estuaries and lagoons to become productive, and permanent coastal settlement to make sense for the first time. Several of the earliest complex societies form on deltas that did not exist before this.